C Class Signal Processors TUBE MICROPHONE/INSTRUMENT PREAMPLIFIER WITH DIGITAL OUTPUT Safety Instructions Caution: To reduce the hazard of electrical shock, do not remove cover or back. No user serviceable parts inside. Please refer all servicing to qualified personnel. WARNING: To reduce the risk of fire or electric shock, do not expose this unit to rain or moisture. The lightning flash with an arrowhead symbol within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. Important Safety Instructions 1. 2. 3. 4. 5. 6. 7. 8. 9. Please read all instructions before operating the unit. Keep these instructions for future reference. Please heed all safety warnings. Follow manufacturers instructions. Do not use this unit near water or moisture. Clean only with a damp cloth. Do not block any of the ventilation openings. Install in accordance with the manufacturers instructions. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or third prong is provided for your safety. When the provided plug does not fit your outlet, consult an electrician for replacement of the obsolete outlet. Protect the power cord from being walked on and pinched particularly at plugs, convenience receptacles and at the point at which they exit from the unit. Unplug this unit during lightning storms or when unused for long periods of time. Refer all servicing to qualified personnel. Servicing is required when the unit has been damaged in any way, such as power supply cord or plug damage, or if liquid has been spilled or objects have fallen into the unit, the unit has been exposed to rain or moisture, does not operate normally, or has been dropped. 10. 11. 12. Table of Contents Introduction C valve Features 2 3 Controls and Functions Front Panel Layout Rear Panel Layout Operating the C valve Setting Up the C valve Setting a Good Level Using The C valve For Getting A Sound Using the Low Cut Filter Using the Tube Process Using the Enhancer Using C valve With An External Signal Processor Using the Digital Output Using the Digital Link Jack System Set-ups Stacking and Tilting the C valve C valve Connections C·Class Dual Rack Adapter (optional) Block Diagram Specifications 4-5 4 5 6-13 6-7 8 9 9-10 10 10 11 12 13 14-15 16 17 18 19 20 Copyright 2003, Samson Technologies Corp. Printed October, 2003 Samson Technologies Corp. 575 Underhill Blvd. P.O. Box 9031 Syosset, NY 11791-9031 Phone: 1-800-3-SAMSON (1-800-372-6766) Fax: 516-364-3888 www.samsontech.com Introduction Congratulations! You just purchased one of the most useful audio tools for digital audio recording, C valve from Samson Audio. The C valve is a high quality microphone/instrument tube pre-amplifier offering a tremendous amount of transparent gain with a pristine audio path that terminates in both balanced analog and S/PDIF digital outputs. By using discreet transistor pre-amp topology, along with the warmth from the incorporation of the12AX7 tube, the C valve takes advantage of the latest technology, together with time proven circuit technique. The result; a super clean pre-amp for microphones or instruments with the warmth and personality of a classic unit, which makes C valve the perfect tracking device for any recording situation. And, with the SATURATION control you can dial up specific amounts of harmonics that are right for your recording or performance. An optical limiter with a musical response is built into C valve, which will help you get a good level to your mixer or recorder. The C valve also features a variable LOW-CUT filter and a musical ENHANCE circuit to add a pleasant "high-frequency lift" to the overall sound. To monitor your input levels, the C valve features a six segment LED bar VU meter, along with a classic analog circular VU meter, which displays the output level. In order to bridge the classic sound of the warm mic-pre to today's digital audio world, the C valve features a high quality, 24Bit, A to D converter with a selectable sample rate of 48 or 96K feeding the S/PDIF digital output . In addition, two C valve's can be linked together to make a stereo mic-pre with digital out. The C valve is a perfect addition to any recording studio, especially those using computer based hard disk recorders, as well as for live use to capture that studio sound live. Although this unit is designed for easy operation, we suggest you take some time out first to go through these pages so you can fully understand how we've implemented a number of unique features. In this manual, you'll find a more detailed description of the features of the C valve, as well as a guided tour through the front and rear panels, step-by-step instructions for using the C valve and full specifications. You'll also find a warranty card enclosed-- please don't forget to fill it out and mail it so that you can receive online technical support and so we can send you updated information about other Samson products in the future. With proper care and adequate air circulation, your C valve will operate trouble free for many years. We recommend you record your serial number in the space provided below for future reference. Serial number: Date of purchase: Should your unit ever require servicing, a Return Authorization number (RA) must be obtained before shipping your unit to Samson. Without this number, the unit will not be accepted. Please call Samson at 1-800-3SAMSON (1-800-372-6766) for a Return Authorization number prior to shipping your unit. Please retain the original packing materials and if possible, return the unit in the original carton and packing materials. 2 C valve Features The Samson C valve microphone and instrument pre-amp utilizes the latest technology in circuit design. Here are some of its main features: · · · · A high quality microphone or instrument pre-amplifier using discrete transistor and tube gain cells. On board Limiter for leveling the output is useful in recording and live sound applications. The total amount of harmonic overtones or "warmth" can be controlled using the Saturation control. An Input Gain control is included to maximize the overall input gain stage, handling levels from microphones or instruments. A pre-set "sweetening" equalization curve can be added using the Enhance switch. Positive or negative phase can be selected using the Phase switch. The addition of an Analog VU meter makes it easy to read the Output Level. 48-volt phantom power for powering condenser microphones is available by pressing the LED, backlit, 48-Volt push switch located on the front panel. S/PDIF output via an internal, high quality A-to-D (analog-to-digital) converter sends 24-bit digital audio to hard disk recorders via the rear panel RCA connector. Sample rate selection via the front panel, backlit switch allows 48 or 96K sample rates. Six segment LED Input VU meter displays the level after the Gain control. Convenient 1/4-inch insert points are included for external signal processing. Balanced XLR microphone input and 1/4-inch balanced line input connectors allow easy hook up of mics or instruments. Oversized, rubber bumpers with tilting feet allow several Samson C class units to be stacked and tilted in an ergonomically correct operating position. The stylish, bead blasted, electric blue anodized front-panel is as easy to read as it is to look at. Three-year extended warranty. · · · · · · · · · · · · 3 C valve Layout Front Panel Layout 1 INPUT GAIN ­ Rotary control used to adjust the input level. LOW FREQUENCY ­ This rotary control is used to set the EQ cut off point for the Low Cut filter. INPUT METER ­ Six segment LED VU meter displays the input level after being affected by the Gain control. SATURATION ­ Rotary control used to adjust the total amount of harmonic overtones generated by the tube circuit. PILOT LIGHT - Illuminated indicator that rises in intensity, and when fully lit, signifies the tube circuit is ready for operation. VOLUME ­ Rotary knob used to control the overall Output level. Digital Overload - LED indicator, which when illuminated, displays the digital clipping point of the Analog to Digital converter. VU METER ­ Classic round analog VU meter displays the amount of output level. POWER SWITCH ­ Heavy-duty rocker switch which, when pressed to the "on" position, lights the internal green LED, indicating the unit is powered up and ready for operation. 10 MIC/INST switch ­ This switch is used to select the proper input operating level for either a microphone or a line/instrument signal source. 48 VOLT ­ When pressed in, the switch will illuminate red indicating the 48-volt phantom power is on. PHASE ­ LED backlit switch which will invert the phase of the mic or instrument input. LOW CUT SWITCH ­ Used to engage the variable low-cut filter, which attenuates or rolls-off the low frequency at a rate of 12 dB per octave starting at the point set by the Low Frequency control knob. VOCAL EQ - When pressed in, the push switch activates the Vocal EQ circuit providing a pre-set equalization curve for "sweetening" the signal with a subtle, but useful, airy high-end lift . LIMIT SWITCH ­ When engaged, the LED lights indicating the Limiter circuit is activated. ENHANCE - When pressed in, the switch activates the Enhance circuit which helps restore the high frequencies that can be lost when the signal is being protected by the on-board LIMITER. 48/96 SWITCH - LED backlit switch which is used to select the sampling frequency of the internal A-to-D converter for either 48 or 96 kiloHertz operation. 2 11 3 12 4 13 5 14 6 7 15 16 8 9 17 4 C valve Layout Rear Panel Layout A AC INLET ­ Connect the included AC1800 power supply here. 24 BIT 48 / 96 (DIGITAL OUT)- 24-bit S/PDIF Digital Output on an RCA connector. DIGITAL LINK IN- 1/4-inch input jack for connecting the balanced line output of a second C valve so that the two units work as a stereo unit transmitting the left and right signals from a single S/PDIF digital output. BALANCED OUTPUT ­ 1/4-inch TRS (TIP/RING/SLEEVE) connector for balanced, line level output. RETURN (INSERT) ­ 1/4-inch phone jack for carrying the return signal of the external processing loop. F SEND (INSERT) - 1/4-inch phone jack for carrying the send signal for the external processing loop. INSTRUMENT IN - 1/4-inch phone input jack for connecting signals from instruments or line level devices. MIC INPUT ­ 3-Pin XLR input connector for connecting microphone level signals. B G C H D E 5 Operating The C valve Setting up the C valve Setting up your C Valve tube pre-amp is a simple procedure, which takes only a few minutes: 1. Remove all packing materials (save them in case of need for future service) and decide where the pre-amp is to be physically placed. To avoid potential overheating problems, be sure that there is good ventilation around the entire unit. 2. Plug the provided AC power adapter in the rear AC inlet, but don't plug the power pack into a wall outlet just yet. 3. Set the controls to the following positions: INPUT GAIN LOW FREQUENCY SATURATION VOLUME MIC/INSTRUMENT 48-VOLT 6 90 1 -10 OUT OUT PHASE LOW CUT VOCAL EQ LIMIT ENHANCE 48 / 96 OUT OUT OUT OUT OUT 48 (OUT) 4. Using a standard XLR microphone cable, connect your microphone to the MIC input located on the rear panel. If you are using an instrument like a guitar or bass guitar, use a standard 1/4-inch phone cable and connect the instrument to the INST input located on the rear panel. For a detailed wiring guide, see page 16 in this manual. 5. Now, connect the rear panel output to your mixer or recorder. 6 Operating The C valve Setting Up the C valve (continued) 6. Plug the C valve power pack into a wall outlet and switch the unit on by pressing the power switch. 7. If you are using an instrument with your C valve, press the MIC/INST switch in to set the C valve's input to accept instrument levels. The LED will illuminate. If you are using a microphone skip this step and go on to the next step. 8. The C valve features on board 48-volt phantom power supply for connecting condenser microphones. IMPORTANT NOTE: With all phantom power supplies, you can get an annoying POP when you engage the phantom power supply, or when you unplug a cable that has phantom power on it. Depending how loud you ...